The applicant wishes to continue a focused career, investigating social-emotional development in early childhood. Earlier research on emotional signaling processes will be extended. Three longitudinal studies will be carried out across periods that span a number of developmental shifts. Developmental shifts are deemed important because they mark a transition in the child that sets the stage for other developmental acquisitions that may be pervasive-both in the child and in the family. One longitudinal study assesses changes In emotional communication and regulation that occurs as a consequence of the developmental shift in early language production between 16-30 months. Hypotheses, derived from our earlier study of the developmental shift of walking onset, will be tested; these concern major differences in emotional signaling and in temperament that are predicted to characterize normal children who enter the shift earlier as opposed to later. Methods in this study Include home and laboratory observations, as well as a new parental report instrument for language acquisition. A second longitudinal study assess changes In emotional communication and regulation across developmental shifts involving the onset of the child's ability to organize coherent emotional narratives between three to seven years. Such narratives reflect internalizations of moral standards and procedures, as well as family role relationships and conflict experiences. Children's narratives are elicited by standard laboratory techniques that are supplemented by home observations. A third study uses a behavioral genetics approach for assessing continuities and change in emotionality. A current longitudinal twin study makes repeated home and laboratory observations at age points from 14 months through five years, and research plans Include extending our observations to the seven to nine-year age period. Measures from our laboratory involving emotional signaling and organization are combined with measures from other laboratories involving cognition, temperament, and empathy.